RETROGRADE INTRARENAL SURGERY (RIRS): CAREFUL INDICATIONS WARRANT MORE SATISFACTIONS!
Renal stones not amenable to, or in which extracorporeal lithotripsy (ESWL) has failed, are prone to percutaneous nephrolithotomy (PCNL), which represents the first option in renal stones larger than 2 cm at our institution. In recent years refinements in ureteroscope design, availability of new generation flexible ureteroscopes along with increasing skill and experience made it increasingly attractive to adopt the ascending route to get to the kidney. But an uncontrolled extent of the indications (i.e. stone volume) can easily lead to worse outcome and early recurrence. Herein we evaluate our preliminary experience with retrograde intrarenal surgery (RIRS), paying special attention to a balanced indication strategy, in order to reduce the risk to require more sessions or to switch to secundary PCNL.
Methods and results
Indications to RIRS were: calculi not exceeding 2 cm in maximum diameter, ESWL failure or patient refusal, highly symptomatic stone (± nephrostomy). Fortyseven patients (all but one with a monolateral intrarenal stone) were recruited from July 2009 to February 2014 to undergo RIRS and laser lithotripsy. They were 35 males and 12 females, with median age 60.5 (range 30-81). Procedures were conducted under general or spinal anesthesia, performed by five surgeons (4 of which had no previous experience in this setting). Mean operative time was 90 minutes (range 30 to 213). One session was conducted in 45 patients, while 2 patients required two treatments. Stone free rate was 87% (42/47 pts). In 6 cases the procedure failed, due to inability to visualize or reach the stone with a laser fiber or a basket: they were subsequently treated with PCNL. No major complications were registered: 1 patient experienced urinary sepsis, while 2 patients required hospitalization longer than 3 days due to persistent discomfort (flank pain or intolerance to JJ stent).
PCNL represents an established treatment modality in kidney stone disease, providing a high stone-free rate (between 78% and 95%1,2). Nevertheless it is not devoid of significant complications, among them requirement for transfusion (11 to 17%1). Improvements of flexible ureteroscopes in terms of caliber, visualization and deflection properties, along with refinements of auxiliary tools (like guidewires, access sheaths, baskets and laser fibers) paved the way to a progressive extension of the indications to a retrograde approach to the kidney. Ureteroscopy is increasingly attractive, because technical advances make it less demanding and because major complications are pretty uncommon and decreasing with time. This has led to a significant extension of indications, mainly in terms of stone burden, with two major disadvantages and consequences: need of multiple procedures and risk of early recurrence. RIRS is reported to require a mean of 2.3 procedures to clean the kidney3 while PCNL can provide up to 95% stone-free rate after the first treatment4. On the other hand, treating complex renal stones (> 2 cm) with RIRS entails a high rate of recurrence (16%) within the first six months5. Due to these reasons, we adopted a cautious approach, setting the upper limit of the stone burden suitable for RIRS at 2 cm, and reserving larger calculi for PCNL. In conclusion, RIRS can be best served if we allocate it in a well defined space, potentially destined to enlarge due to technological advances, without thinking of it as a modality intended to remove PCNL from its current role.
1. Michel MS et al., Eur Urol 2007; 51: 899
2. Preminger G et al., J Urol 2005; 173: 1991
3. Breda A et al., J Urol 2008; 179: 981
4. McDougall E: Percutaneous approaches to the upper urinary tract. In: Campbell’s Urology, 8th ed. Philadelphia: WB Sanders Co 2002; pp 3320–3360
5. Miller NL and Lingeman JE: Management of kidney stones, BMJ 2007; 334: 468